Молекулярная гастрономия для креативных шеф-поваров (англ. язык) - страница 128

Молекулярная гастрономия для креативных шеф-поваров (англ. язык)

not too low) so can be used to make a large number of jellies.

Elasticity

Gels made with agar agar have the disadvantage that the gel formed is easily broken and not as

elastic as gelatine – however elasticity can be improved by the addition of sorbitol or glycerol (more

commonly named glycerine) to the gel base, although these products are associated with laxative

effects.

Limitations

Because the preparation needs to be boiled to dissolve the agar agar, it is not useful for gels that are

to be mad from “raw” liquids (such as fresh parsley, oysters, gazpacho, etc.) – however, this problem

III/X - 3 (of 5)

can to extent be overcome by just dissolving the desired amount of agar agar in a very small quantity

of boiling liquid, and adding this to the large amount of raw liquid, to keep the “fresh” taste, however,

the gel will form very quickly and is difficult to handle.

Alginate

Alginate is a gelling agent extracted from brown algae. It is composed of long strands composed of the

two basic subunits – gluronic acid and mannuronic acid:

gluronic acid

manuroic acid

How it works

When alginate is added to a liquid, it will act as a thickener. In the presence of calcium ions, a mixture

containing alginate will form a gel. The calcium ions insert themselves between individual alginate

strands and will allow them to interlock and form a gel, in an arrangement similar to an egg box.

Alginate strands (zig zag lines) forming...

es between individual alginate

strands and will allow them to interlock and form a gel, in an arrangement similar to an egg box.

Alginate strands (zig zag lines) forming a network around the Ca ions present (circles)

The ability of a certain alginate to thicken or gel will depend on its relative proportions of gluronic and

manuronic acid (for example, alginates high in gluronic acid will be more effective gelling agents).

Because alginate forms gels uniquely in the presence of calcium, the food industry used it to make

“fake caviar”: drops of an alginate containing solution are slowly pipetted into a large bowl of water

containing a high concentration of calcium ions – the outside of the drop, which is in contact with the

calcium, will instantly form a gel, while the centre of the bead, which is not in contact with the calcium

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